Rust-resistant iron



Patented Apr. 28, 1925.

.UNITED STATES PATENT OFFICE.

HARRY A. SCHWARTZ, OF CLEVELAND, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 NATIONAL MALLEABLE AND STEEL CASTINGS COMPANY, OF CLEVELAND,

OHIO, A CORPORATION OF OHIO.

RUST-RESISTANT IRON.

No Drawing.

To (17f 1072 0m it may concern:

Be it known that I, HARRY A. Sorrwan'rz, a citizen of the United States, residing at Cleveland, Cuyahoga County, Ohio, have invented new and Improw'ed Rust-Resistant Iron, of which the following is a specification. I

My invention relates to rust resistant iron, and particularly to malleable cast iron, and comprises th addition of an alloying element,' which does not affect the graphitization of the casting during the malleablizing process, such as copper, nickel, or cobalt, for the purpose of improving the rust resisting qualities of the iron. Additions of copper in small percentages have been found to be particularly effective in bringing about such a result.

I have found that when a small amount of copper which in the final product doesnot exceed about 25%, preferably above and as near as possible, is added, a copperiron alloy is formed which has a much greater resistance to rusting than the ironconstituent by itself. 'I believe from experiment that the limit of solubility of copper in iron is about 25%, and that if copper substantially in excess of this limit is present the excess remains inthe casting in what appear to be unabsorbed minute particles, which contain a high percentage of copper, and these minute particles set up an electrolytic action with the iron which results in a more rapid rusting than would be the case if no copper whatever is added.

In the resulting product, when malleablized, carbon, manganese, silicon, ctq-., appear in'the usual percentages, and, so far as I have been able to ascertain, these substances have no effect upon the copper and l'llB'COPPCIKllllS no effect upon them.

It is my experience that in malleable cast iron containing from 2.25% or higher of carbon very greatly improved rust resisting qualities areobtained without affecting the other desirablequalities of the iron. For instance, in malleable cast iron of such a Application filed February 24, 1922. Serial No. 538,979;

composition I have found that the rusting proceeds about two-thirds to one-seventh as fast as in ordinary malleable cast iron, depending upon the conditions to which the iron is submitted. It is obvious that my invention is of particular value inconnection with stove castings; radiator connections, including nipples; pipe fittings; and other uses in which rust resisting qualities are desirable.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in th use of such terms and expressions, of excluding any equivalents of the features shown or described, or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

What I claim is:

1. A highly rust resistant malleable iron casting containing approximately between .15 and 25% ofcopper and forming with the iron a copper-iron alloy, and having such percentages of carbon, manganese, silicon and the like as are usually present in malleabl cast iron.

2. A highly rust resistant malleable iron casting having therein an amount of copper up to, but not substantially exceeding, the limit of the solubility of copper in iron, said casting containing also carbon, manganese, silicon and like elements in the percentages normally found in malleable cast iron.

3.-A radiator nipple comprising a highly rust resistant malleable iron casting containin-gcopper in an amount up to, but not substantially exceeding, its limit of solubility in iron and beingwithout effect on the graphitization of the casting during malleablizing, the casting containing also such percentages of carbon, manganese, silicon and like elements as are normally found in 'nalleable cast iron.

HARRY A. SCHW'ARTZ. 

